Lubricating oil



or dispersed in lubricating oils.

Patented Oct. 12, 1948 LUBRICATING OIL Rush F. McGleary, Beacon, and Stiles M. Roberts,

Glenham, N. Y., assignors to The Texas Company, New York, N. Y., a corporation of Delaware No Drawing. Original application May 13, 1941, Serial No. 393,244, now Patent No. 2,322,376, dated June 22, 1943. Divided and this application December 5, 1942, Serial No. 468,000

This invention relates to an improved lubricating oil adapted for use in internal combustion engines and particularly to a lubricating oil having one or more additive ingredients incorporated therein.

This invention is a division of the invention as described and claimed in the copending application of Rush F. McCleary and Stiles M. Roberts, Ser al No. 393,244, filed May 13, 1941, now Patent No. 2,322,376, dated June 22, 1943.

It is generally conceded that in the recent development of internal combustion engines, and particularly engines designed for heavy duty service, the increase in operating temperatures, together with the reduction of clearances and the use of hard bearing alloys, such as copper-lead, cadmium silver, etc., have set up such severe operating conditions as to necessitate an improvement in the highly solvent-refined mineral oils refined for use as lubricants. These rigorous operating conditions which are most prevalent in Diesel and gasoline engines used in heavy duty bus and tractor service, where the piston ring temperatures range from approximately 425 to 650 F. and pressures from the oxidizing combustion gases are as high as '750 to 1150 pounds per square inch, have seriously accentuated such problems as corrosion, oxidation and resin formation in the solvent-refined mineral lubricating oils with the resultant deleterious effect on the efliciency of the engines. The nature and extent of these problems depends upon the conditions of operation of the particular engine type, the type and extent of refining of the base oil used, and numerous other factors.

The tendency of mineral lubricating oils to deposit gums, resins, soot, and varnish-like materials about the valves, rings, pistons, cylinders and other engine parts can be largely overcome by the addition of certain types of additive ingredients which possess detergent properties when dissolved By detergent property is meant not only that property which aids in dispersing, removing or purging foreign materials which accumulate on the surface of the engine parts but also that property which prevents the accumulation or deposition of such materials as distinguished from solvent action upon those accumulations or deposits.

In addition thereto, theadded tendency of 12'Claims. (Cl. 252-42.?)

these oils to corrode the metal surfaces with which the lubricating oil comes in contact may be overcome or reduced by the addition of additive components which possess anti-oxidant or anti-corrosive properties when dissolved or dispersed in mineral lubricating oils. These anti-oxidant or anti-corrosive properties are meant to include all such properties which effect a reduction or elimination of weight loss of the lubricating sur faces, particularly bearing surfaces, which result from the corrosive action of the mineral lubricating oil.

It is the object of the present invention to provide a mineral oil composition which possesses the above-mentioned detergent and anti-oxidant or anti-corrosive properties by incorporating in a mineral lubricating oil a novel additive ingredient of multi-functional activity.

A further object of this invention is to provide a mineral oil compositionpossessing detergent properties and enhanced anti-oxidant or anticorrosive properties by combining with the abovementioned multi-functional additive an auxiliary additive ingredient and incorporating the combination in a lubricating mineral oil.

The invention is based upon the discovery of a novel class of multi-functional additives which may be broadly described as oil-soluble or oilmiscible hydroxy, aromatic or mercapto aromatic methylene thioethers and/ or the metal derivatives thereof. It has been found that when small proportions of a compound within the scope of the above-general class are blended with a mineral lubricating oil, a mineral oil composition is formed possessing excellent detergent and anti-oxidant or anti-corrosive properties. The compounds of the present invention may be described as that class of aromatic compounds which contain at least one radical of the type -CH2-S-R1 attached to a nuclear carbon atom and at least one hydroxyl (OH) or sulfhydryl (SI-I) radical or their metal salts. Specifically these compounds may be represented by the following structural formula Ry (CH2S-R1).

in which R may be a hydrogen, alkyl, aryl, cycloalkyl, aralkyl or naphthenyl radical, and R1 may be an alkyl, aryl, cycloalkyl, aralkyl or naphthenyl radical. These radicals may contain further substituents which do not afiect the oil-solubility of the compound, as, for example, halogen, sulfur, oxygen, or nitrogen derivatives. X may be either a hydroxyl (OH) or sulfyhydryl (SH) radical or metal salts thereof, and n, y and a are integers of 1 or more. y and 2 are usually either 1, 2, 3 or 4, whereas 11 may be either 1, 2 or 3, depending upon the valences of the aromatic nucleus not satisfied by other substitutents or residual hydrogen. The aromatic nucleus diagrammatically shown may be substituted by a naphthyl, anthracyl or any other condensed aromatic nucleus. The positions of the 15 substituents are purely diagrammatic and may be connected to any position in the aromatic nucleus. The metal derivatives of this class of compounds which are formed by the substitution of the replaceable hydrogen in the hydroxyl radical (OH) or the sulfhydryl radical (SH) include any of the following metals: sodium, potassium, lithium, calcium, barium, strontium, magnesium, zinc, iron, cobalt, nickel, aluminum, manganese, and chromium.

As illustrating the type of compounds within the scope of the above classification, the following compounds are presented, together with their relationship to the general classification. It is to be understood that the above-mentioned metals may be substituted for the replaceable hydrogen in the following compounds and that the scope of the present invention is not limited to the following specific compounds or their n, y= 1, z=2 X OH Di (bntylthioniethyl) oetyl phenol H Di (butylthiomcthyl) octyl thiophenol 71 1, y=2, 2 Amylthiomethyl dioctadecyl naphthol X SH Amylthiomctllyl dioctadecyl thionaphthol n=1 y, 2:2, X OH Di (octylthiomethyl) diamyl phenol H D1 (octylthloniethyl) (llamyl thlophenol n=3, y, 2 1, X: OH Amylthiomethyl undecyl pyrogallol n=2, y=1 z=2, X=OH Di (amylthlomethyl) undecyl resorcinol n=3, =2 2:1, X=OH Amylthlomethyl dioctyl pyrogallol In the following compounds X is a hydroxyl radical, although the corresponding thio compounds, e. g., where X is a sulfhydryl radical, may also be used:

R hydrogen, R alkyl n 1, y 3 z 2 Di (butylthlomethyl) phenol n 1 y 2, z= 3 Tri (oetylthiomcthyl) phenol l1, 2 Di (amylthiomethyl) resorclnol n 2, y 1, z 3 Tri (amylthiomethyl) resorcinol R=cyc1oalkyl, R =alkyl 2: l Butylthiomethyl cyclohexyl phenol 'n, y= 1 2:2 Di (butylthiomethyfi cyclohexyl pllenol n= 1, y: 2, z 1 Butylthiomethyl di-cyclohexyl phenol n y z: Octylthiomethylcylohexyl resorcinol n 2 y 1, z 2 Di (octylthiomethyl) cyclohexyl resorcinol 11 I Z: Octylthlomethyl dl-cyclohexyl resorclnol R= aralkyl, R alkyl 2: 1 Hexylthiomethyl benzyl naphthol n, y 1 z 2 Di (hexylthiomethyfi benzyl naphthol n 1 y: z: 1 Hexylthiomethyl dibenzyl naphthol Hexylthiomethyl benzyl resorcinol n 2, y 1, z Di (hexylthiomethyl) benzyl resorclnol n, 2, z 1 Hcxylthiomet yl dlbenzyl resorcinol R= aryl- R alkyl y! z=1 Amylthiomethyl phenyl phenol n, y: 1, .2: Di (amylthlomethyl) phenyl phenol 'n y= z: Amylthlomethyl dlphcnyl phenol z Amylthiomcthyl phcnyl resorcinol n: y: z=2 Di (amylthiomethyl) phenyl resorcinol y 1 Amylthlometnyl dlphcnyl resorelnol R=naphthenyl, R alkyl y, 1 Octylthiomethyl naphthenyl naphthol 71, y: 2: Di (octylthiomethyl) iio liilion l naphthol n: l 2/: z: Octylthiomethyl naphthenyl pyrogallol n 2, y 1, z 2 Di (octylthiomethyl) naphthenyl resoreinol R= alkyl, R aryl D1 (phenylthlonlethyl) resorclnol R=alky1,. R cycloalkyl n, z: 1 Cyclohexylthiomet yl octadecyl naphthol n, 1, z= 2 Di (cyclohexylt ioniethyl) octadecyl naphthol n= 1, y, z: 2 Di (cyclohexylthioinethyl) dioctadecyl naphtha] n 1, y 2 z 1 Cyclohexylthiomethyl diamyl phenol n= 2, y z: 1 Cyclohexylthiomcthyl octyl tesorcinol n 2, y 1 z 2 D1 (cyclohexylthlomethyl) oetyl resorcinol n, y= 2, 2: 1 Cyclohexylthiomethyl dioctyl resorcinol R hydrogen, R cycloalkyl n= 1, q=3, z=2 Di (eyclohexy thiomethyl) phenol n=1, 1=2, z=3 5 Tri (eyclohexy thiomethyl) phenol n=3 y: 2:2 Di (cyclohexylthiomethyl) pytogallol n y z: Di (cyclohexylthiomethyl) hydroquinone R alkyl, R aralkyl 'n, y z=1 Benzylthiomethyl cctyl phenol n y: z= Benzylthiomethyl diundeoyl hydroquinone R hydrogen, R aralkyl n 1, y 3, z 2 Di (benzylthiomethyl) phenol n 1 y 2, z 3 'Iri (benzyl thiomethyl) phenol n 1 Z: Di (benzyltliiomethyl) resorcinol R=alkyl, R1=naphtheny1 n y z=1 Naphthenylthi omethyl octyl naphthol n, y 1, z=2 Di (naphthenylthiomethyl) octyl naphthol 77, y 2 z Naphthenylthiomethyl dioctyl naphthol 1 n z 1 Naphthenylthiomethyl undecyl resorcinol n 2, y 1 z 2 Di (naphthenylthiomethyl) unclecyl resorcinol R hydrogen, R naphthenyl n 1, y 3, 2- Di (naphthenylthiomethyl) phenol I 1/ Z: D1 (naphthenylthiomethyl) resorcmol R=tertiary aminomethyl, R =alkyl n l y 2, z 1 Amylthiomethyl di (dimethtlylaminomethyl) phenol n z Di (amylthiomethyl) di methylamhiomethyl phenol y z Amylthiomethyl niorpholiomethyl resorcinol The general class of compounds represented by the foregoing may be prepared by the following reaction: 7

They may also be prepared by the interaction of alkylated phenol, formaldehyde and mercaptan as shown: 7

However, any of the other classical methods of synthesis may be used, and the following ex amples are mentioned as illustrating one method of preparation:

Example I In preparing amylthiomethyl octyl phenol according to reaction No. 1, 106 grams of dimethylaminomethyl octyl phenol and 218 grains of mercaptan were intimately mixed with agitation and refluxed for 35 hours. given off and after the evolution was complete the reaction mixture was transferred to a distilling flask and distilled under vacuum. The product was collected at to 190 C. at three millimeters pressure. The resulting amylthiomethyl o'ctyl phenol was obtained as a clear, light yellow liquid (B. P. -1'70 C. at three millimeters mercury) and analyzed 9.3% sulfur.

Example II 65 grams of amylthiomethyl octyl phenol, 22 grams of barium hydroxide, and 250cc. of toluene were intimately mixed under agitation, and refluxed under an automatic water separator 'until no more water was eliminated from the reaction. Filter-eel was added to the reaction mixture and theexcess barium hydroxide filtered out. The filtrate was freed of toluene by heating under vacuum and the resulting barium amylthiomethyl octyl phenolate was obtained as a clear, brittle, light-brown solid, which was dissolved in an equal weight of lubricatin oil. The 50% concentrate analyzed 8.3% barium and 4.35% sulfur.

Example III A partially substituted product was obtained by reacting tri (dimethylaminomethyll phenol under mild conditions in accordance with reaction No. 1. In this reaction 265 grams of tri(dimethylaminornethyl) phenol, 500 grams of amyl mercaptan, and 400 cc. of toluene were stirred together and refluxed for 60 hours. given off and after the evolution was complete the tolueneand excess amyl mercaptan were distilled off at atmospheric pressure and a small intermediate fraction was collected which. boiled up to 150 C. at 10 millimeters mercury. The residual amylthiomethyl di-(dimethylaminomethyl) phenol appeared as a light-brown oil and analyzed 7.42% sulfur and 9.02% nitrogen.

The proportions of these multi-functional additives added to a mineral lubricating oil may vary between 0.1 and 5.0% 'by weight, depending upon the particular base oil used and the type of engine and service involved. However, the and proportions between 0.25 and 2.0% by weight have been found to be particularly effective in incparting excellent detergent and anti-corrosive properties to the mineral lubricating oil.

An additional feature of, the present invention is a combination of the foregoing multi-functi-onal Dimethylamine was Dimethylamine was additives with an auxiliary additive to further enhance the anti-oxidant or anti-corrosive properties of the mineral oil composition with which the additives are used in certain Diesel and gasoline engines designed for heavy duty service. A higher degree of anti-oxidant or anti-corrosive properties is desired and it is for this purpose that an auxiliary additive ingredient is added to the compounds aforementioned.

The class of compounds which may be used to impart the additional anti-corrosive properties may be any one of the generally accepted sulfurized anti-corrosives. Among theparticularly effective sulfurized anti-corrosive compounds found suitable for purposes of the invention are the sulfurized esters of oleic acid, such as sulfurized ethyl oleate; sulfurized high-boiling gasoline polymers, such as the sulfurizedclaytowerpolymers; sulfurized fatty oils, such as sulfurized sperm oil sulfurized wax compounds, such as sulfurized paraffin wax; sulfurized resins, such as sulfurized abietene; sulfurized tall oil; and sulfurized terpene hydrocarbons, such as the sulfurized terpinolenes and isomers thereof, which are disclosed and claimed in the copending application of Knowles, McCoy and Patterson, Serial No. 391,468, filed May 2, 1941, now Patent No. 2,417,305 dated March 11, 1947. The amount of sulfurized compound added to the mineral lubricating oil in combination with the multi-functional additive is usually within the proportion range of 0.5 and 5.0% 'by weight and preferably between 1.0% and 3.0%, depending upon the type of lubricating oil used.

These sulfurized auxiliary additives may be prepared by the direct action of sulfur on the material to be sulfurized at approximately 300 F. in the presence of water and under pressure of hydrogen sulfide. This pressure, which is at least 50 pounds per square inch, is maintained until all the free sulfur has entered into combination which usually requires from one-half to three hours. The sulfurized products formed by this process are directly soluble in a mineral oil and possess the added advantage in that the reaction product is a light-colored compound as against the usually dark-colored sulfurized compounds.

As illustrative of the anti-corrosive properties of a lubricating oil containing either or both of the aforementioned class of compounds, the results of the following empirical tests are presented. A copper-lead bearing specimen, encased in a special non-wear bushing and rotatably mounted on a stainless steel shaft, was immersed in a glass pot of the oil to be tested. The tested oil was heated to a controlled temperature of either 250 F. or 350 F. and continuously circulated between the bearing specimen and the shaft for 10 hours. The bearing specimen was weighed before the test and after the 10 hour period and the loss in weight recorded in milligrams. Two reference oils were used in this test and will be referred to as Reference Oil A and Reference Oil B. Both of these reference oils were solvent-refined, dewaxed Mid-Continent lubricating oil distillates of SAE 30 grade, reference oil A being a parafiln-naphthene (1:1) base oil and reference oil B being a parafiin base oil. To these reference oils were added varying proportions of the additives of the present invention taken individually and in combination and the results compared. The results of two runs at both 250 F. and 350 F. are presented:

Bearmg COTTOSZOnCOppT lead (10 hours) [Loss of weight in mgs.]

Oil Tested 250 F. 350 F.

Reference Oil A. 4, 6 142,177 Reference Oil 13 4, 5 167,199 Reference Oil B"+0. amylt omethyl octyl p enol 1,2 26, 51 Reference Oil B+0.5% amylthiomethyl di (dimetbylaminomethyl) phenol 0, 0 15, 35 Reference Oil A+0.5% barium eniylthiomethyl octyl phenolate 0, 1 138,161 Reference Oil A+0.5% barium amylthiomethyl octyl phenolate+3.0% sulfurized sperm oil 1.1 46, 10 Reference Oil A+0.5% barium amylthiomethyl octyl phenolate+1.0% sulfurized terpinolene O, l 0, 0 Reference Oil A+0.5% barium amylthiomethyl oct-yl phenolate+3.0% sulfurized clay tower polymers 2, 0 l, 0 Reference Oil A+0.5% barium amyltbiomethyl octyl phenolatc+2.0% sulfurized ethyl oleate 1,2 3.2

An illustration of the detergent properties of the additives of the present invention may be shown by the results of an empirical test which was designed to indicate the performance of the additives in preventing the accumulation or deposition of varnish or lacquer deposits on the engine parts. This test is carried out in a single cylinder standard Lauson engine by operating with the compounded oil of the present invention under extremely severe conditions for the purpose of developing varnish and lacquer. The conditions of operation attempt to simulate the severe operating conditions encountered in the field by running the engine continuously at 1800 R. P. M. for 24 hours, with the jacket temperature at 212 F., the crankcase temperature at 300 F., fuel fed at 10 cc. per 30 seconds, and a crankcase ventilation of 0.4 cubic foot of air per minute. At the end of this period the engine was dismantled, the piston removed and examined, the amount of varnish deposited upon the piston determined, and the oil classified according to a visual classification of A, B, C, D and E (A=clean; B=light varnish; C medium varnish; D==heavy varnish; and E=very heavy varnish). The following results were obtained with a solvent-refined, dewaxed Mid-Continent lubricating oil of an SAE 20 grade as the reference oil, and compared with the reference oil containing the proposed additive:

Lauson engine varnish test As a final test to indicate the effectiveness of the compounded oils proposed by the present invention under actual operating conditions, a special test was devised which is a modification of the test described in a Diesel Lubricant Test Manual, Laboratory Test No. 1, put out by the Caterpillar Tractor Company. This test was carried out in a single cylinder Diesel engine operating at 900 R. P. M. with a water jacket temperature of 175 F. and run continuously for periods of 120 and 240 hours, or until rings are stuck, as indicated by the increase in blowby. The crankcase oil was drained every hours and fresh oil added thereto. At the end of the and 240 hour runs the engine was thoroughly and at least'one'f'urther substituent linked to an additional nuclear carbon atom selected from the group consisting of sulfhydryl radicals and themetal salts thereof.

6. An improved lubricant comprising a major Engine Part Reference Oil Reference Oil +0.5% Barium Amylthiomethyl Octylphenolate W Piston Grown:

120 Hours Normal 240 Hours do Piston Rings: w

120 Hours Nos. 3 and 4 slight lacquer; Nos. 5 and 6 sludge deposit 240 Hours Nos. 1, 2 and 3 clean but No. 1 ring 90% stuck in ring groove; Nos. 4, 5 and 6 show lacquer on top of ring and signs of sticking.

Ring Grooves:

120 Hours All clean 240 Hours No. 1 hard carbon build-up; Nos. 2, 4, 5 and 6 black lacquer; No. 3 trace of lacquer.

Piston Skirt:

120 Hours 1" ring of heavy brown varnish and other spotted areas; 4 dark brown varnish formation extending along axis of piston.

240 Hours 2 ring of brown varnish around piston and 3 blackbrown varnish formation along axis of piston. Under Piston Deposit:

120 Hours 240 Hours Black, granular deposit- Oil Filter:

120 Hours Light coating of lint sludge 240 Hours Surface covered with lint sludge, no mesh vis with No. 5 sticking and No. 6 slight sticking.

Normal.

Do. Nos. 1, 2 and 3 clean; No. 4 heavy lacquer; No. 5 lacquer; No. 6 light lacquer; No ring sticking.

6 lacquer; No ring sticking.

No. l trace deposit; Nos. 2 and 3 heavy lacquer; No. 4

lacquer; No. 5 light lacquer; No. 6 heavy varnish. Nos. 1 and 2 trace deposit; Nos. 3, 4 and 5 heavy lacquer;

No. 6 lacquer.

Trace of varnish on thrust side and 3 brown varnish formation along axis of anti-thrust side.

Trace varnish both thrust an'danti-thrust sides.

Trace. Same as 120 hrs.

Covered with lint-mesh outline visible. Covered with lintmesh pattern visible.

The multi-functional additives of the present invention may further be used in combination with other additive ingredients suchas pour point depressors, oiliness agents, extreme pressure agents, blooming agents, viscosity index improving agents, color stabilizers, etc., without depart-- ing from the spirit of the invention.

Obviously many modifications and variations of the invention, as hereinbefore set forth, may be made without departing from the spirit and scope thereof and therefore only such limitations should be imposed as are indicated in the appended claims.

We claim:

1. An improved lubricant comprising a major proportion of a, mineral lubricating oil having incorporated therein a small proportion, sufficient to stabilize said oil, of an oil-miscible alkyl thiophenol methylene thioether.

2. An improved lubricant comprising a major proportion of a mineral lubricating oil having incorporated therein a small proportion, suflicient to stablize said oil, of an'oil-miscible metal salt of an alkyl thiophenol methylene thioether.

3. An improved lubricating oil comprising a major proportion of a mineral lubricating oil to stabilize said oil, of an oil-miscible mono nuclear aromatic methylene thioether containing at least one substituent linked to a nuclear carbon atom of the type -CH2S-R1 in which R1 is a radical from the group consisting of alkyl, aralkyl, aryl and naphthenyl radicals,

, to stabilize said oil, of an oil-miscible mono-nuclear aromatic methylene thioether containing a metal sulfide radical linked to a nuclear carbon atom.

8. An improved lubricating oil comprising a major proportion of a mineral lubricating oil having incorporated therein a small proportion, sufficient to stabilize said oil, of an oil-miscible mono-nuclear aromatic methylene thioether cont-aining at least one substituent linked to an aromatic nucleus selected from the group consisting of sulfhydryl radicals and metal salts thereof, and a sulfurized additive ingredient possessing anti-corrosive properties.

9. An improved lubricant comprising a major proportion of a mineral lubricating oil having incorporated therein 0.1 to 5% by weight of an oil-miscible mono-nuclear aromatic methylene thioether .containing at least one substituent linked to the aromatic nucleus selected from the group consisting of sulfhydryl radicals and the metal salts thereof, and a sulfurized additive ingredient selected from the group consisting of sulfurized esters of oleic acid, sulfurized highboiling gasoline polymers, sulfurized fatty oils, sulfurized wax compounds, sulfurized resins, sulfurized tall oil, and sulfurized terpene, hydrocarbons. I

10. An improved lubricant comprising a major proportion of a mineral lubricating oil having incorporated therein 0.1 to 5% by Weight of an oilmiscible mono-nuclear aromatic methylene thioether containing at least one substitutent linked to the aromatic nucleus selected from the group consisting of sulfhydryl radicals and the metal salts thereof, and a sulfurized fatty oil.

11'. An improved lubricant comprising a major Nos. 1, 2 and 3 clean; Nos. land 5 heavy lacquer; No.

11 proportion of a mineral lubricating oil having incorporated therein 0.1 to 5% by weight of an oilmiscible mono-nuclear aromatic methylene thioether containing at least one substitutent linked to the aromatic nucleus selected from the group consisting of sulfhydryl radicals and the metal salts thereof, and a sulfurized wax compound.

12. An improved lubricant comprising a major proportion of a mineral lubricating oil having incorporated therein 0.1 to 5% by weight of an oil-miscible mono-nuclear aromatic methylene thioether containing at least one substituent linked to the aromatic nucleus selected from the group consisting of sulfhydryl radicals and the metal salts thereof, and a sulfurized terpene hydrocarbon.

RUSH F. McCLEARY.

STILES M. ROBERTS.

REFERENCES CITED The following references are of record in the tile of this patent:

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